Interactive television (iTV) is currently available in varying forms and there is perhaps no single, universally accepted definition for this term. Most, however, would agree that iTV systems combine, in some form or other, the passive viewing experience of traditional TV viewing with the interactive nature of external data and content sources such as the World Wide Web. Thus, in different implementations, iTV might allow viewers (perhaps more appropriately termed subscribers) to review local news headlines or weather forecasts while watching their favorite television shows, to chat with other viewers about the latest plot twists. Many cable and satellite TV providers have deployed iTV systems that allow subscribers to order products seen in commercials or video on demand presentations with the click of a remote control button. And certainly all iTV systems have a version of an interactive program guide that allows subscribers to learn about and select desired programming. The terminology used to describe the various elements within the iTV services and applications landscape is varied and a glossary of terms used herein is set forth in Appendix A.
A specific service offered within the iTV landscape is enhanced TV (ETV) broadcasting that provides interactive content linked to video programming. A user can request information on products within ads, access additional program information such as sports statistics, or otherwise interact with a television broadcast such as a game or reality based show. This functionality is achieved through the execution and transmission of an ETV application and corresponding data sent in the broadcast channel or other mechanism along with the video broadcast.
These and other iTV services are deployed as a set of applications over the service provider's network. Such applications are received at the subscriber's premises via a set-top box or similar device, where they are interpreted (compiled), executed and the corresponding data is displayed on a television.
Many applications may be presented to end users via a common user interface and order/transaction entry and tracking system. However, each application has specific integration, management and distribution issues that arise depending on the environment that the network operators choose to deploy and significant problems are experienced by application providers and distributors in deploying and managing their ETV applications as a result. Stated differently, application providers and distributors face problems in developing and managing their ETV applications because there exists a proliferation of technologies and standards for the delivery of ETV applications and different network operators have chosen to deploy different combinations of these technologies. For example, ETV application providers must cope with networks that have been cobbled together with different technologies such as:                1. Head-end technology from different providers such as Motorola, Scientific Atlanta, Harmonic, etc.        2. Set-top boxes from different manufacturers such as Motorola, Scientific Atlanta, Pace, Pioneer, AOL, etc.        3. Various combinations of network topologies such as cable, satellite, terrestrial, and telco, etc.        4. Middleware from providers such as Liberate, OpenTV, MSTV, Canal+, Worldgate, etc.        5. VOD server providers from vendors such as SeaChange, Concurrent, nCube, Diva, etc.        6. Billing systems from companies such as Convergys, CSG, DST, etc.        7. Conditional access systems from vendors such as NDS, Harmonic, etc.        8. Differeing application content standards such as HTML, XHTML, XML, ECMAScript, OCAP, MHP, ATVEF, DASE, etc.        9. Various programming languages, such as Java, C, C++, etc.        
Content providers and application developers must navigate through this maze of often incompatible and unique combinations of the equipment, technologies and standards, and often must develop a unique and different application for each such combination that they wish to target. For their part, network operators must deploy, configure, manage and operate ETV applications on each different network configuration individually, increasing cost, complexity, and staffing needs, while reducing the number of service that can be deployed, and the quality of those services.
System operators must manage the applications within the ETV service. Middleware solutions alone allow only for a collection of applications to be deployed. There is no provision for creating a system of applications that address the following issues:                1. Application validation, which govern rights for application deployment and behavior on the system;        2. High-level views of content placement opportunities across an entire system of applications, an example of which may be the ability for the system operator to “see” advertisement locations across an entire system of applications where that set of applications may have come from a multitude of sources; and        3. Mechanisms for quickly resolving and distributing content to an application from a multitude of content sources.        
Another significant problem for the deployment of ETV applications in the United States is that the majority of in-service set-top boxes, such as the Motorola DCT1200 and DCT2000 families and the Scientific Atlanta Explorer 2000, Explorer 2100, Explorer 3000 and Explorer 3100 families, have relatively low power (e.g., slow clock speed) processors and a limited amount of onboard memory (both flash memory and DRAM) with which to store and process ETV applications. For example, many distributed applications may not be executable on various set-top boxes due to the memory and processing requirements to compile or otherwise interpret the application and data for proper display. These set-top limitations make it very difficult to support the features, functions and viewer response times for ETV applications that are required for a compelling and rich user experience.